• Korean Journal of Agricultural Science
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• v.16 no.2
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• pp.201-211
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• 1989

This experiment was carried out to study the practical utility of Mucor rennet in making Blue cheese and to investigate the changes in the level of various nitrogen compounds. 1. The Mucor rennet cheese, the calf rennet cheese and the mixed rennet cheese did not show any significant difference in their yields. 2. The dry matter contents of Blue cheese was increased during the ripening and the levels of Mucor rennet did not have any influence in these respect. 3. The water soluble nitrogen contents of Blue cheese increased during ripening. On 0 day of ripening the Mucor rennet cheese contained water soluble nitrogen than the calf rennet cheese. On 40 days of ripening the mixed cheese contained less water soluble nitrogen than the calf rennet cheese. 4. Non protein nitrogen, peptone amino nitrogen, water soluble protein nitrogen, proteose nitrogen and peptone nitrogen appeared to contain similar levels of water soluble nitrogen. 5. The results of electrophoresis indicated a greater degredation on as-casein and ${\beta}$-casein in the Blue cheese made with Mucor rennet than in those made with calf rennet. On 60 days of ripening the mixed cheese more casein than did the Mucor rennet cheese. 6. The free amino acid contents of the Mucor rennet cheese was higher than the calf rennet cheese at 60 days of ripening.

• Journal of Dairy Science and Biotechnology
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• v.18 no.1
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• pp.1-8
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• 2000

This experiment was carried out to study fractionation and physicochemical characteristics of caprine casein. Acid caseins obtained from caprine colostral and normal milk were analyzed by chymosin treatment and fractionated by DEAE-cellulose column chromatography with linear gradient and electrophoresis. Protein, fat and lactose of caprine normal milk were 2.70${\pm}$0.27%, 3.82${\pm}$0.51%, and 4.10${\pm}$0.29%, respectively. More non-protein nitrogen(NPN) was released by chymosin treatment from caprine colostral casein than normal casein. The electrophoretic pattern of caprine casein was not similar to that of bovine casein, Caprine normal casein was fractionated by DEAE-cellulose column chromatography with a 0.08${\sim}$0.18 M NaCl linear gradient into 5 pes with the proportion of 5.27%, 26.07%, 25.97%, 30.40% and 12.29%, respectively. In order to identify the pure fraction, the chymosin-treated caprine normal casein was fractionated by DEAE-cellulosecolumn chromatography with a 0.08${\sim}$0.18 M NaCl linear gradient into 6 peaks with the proportion of 17.06%, 9.10%, 17.85%, 20.11%, 27.03% and 8.85%, respectively.

• Journal of Nutrition and Health
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• v.19 no.4
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• pp.224-232
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• 1986

This study was performed to investigate the effects of different kinds of dietary protein [plant protein ; Isolated Soy Protein(ISP), animal protein ; casein] on protein and lipid metabolism in rats fed with coffee and/or methionine in diet during four weeks of growing period after weanling. Forty male growing rats fo Sprague-Dawley strain, weighing 92.5$\pm$1.8g, were distributed into 8 groups by randomized complete block design, and fed diets containing 15% of protein by weight either as ISP or casein and 10% ofcalories as corn oil, supplemented with coffee and /or methionine for 4 weeks. Coffee were added at a concentration of 1.4% of diet as instant coffee, and methionine were added to ISP or casein diet to be 0.6% of diet as DL-methionine. Results were followed ; Body weight gain, F.E. R and P.E.R tanded to be higher in methionine added groups than non-methionine groups. The nitrogen content of feces was significantly higher in coffee groups than non-coffee groups, and tended to be higher in ISP groups than casein groups. but was not significantly different with or without methionine. thus, apparent protein digestilbity was significantly lower in coffee groups than non-coffee groups and was significantly lower in ISP groups than cesein groups, but was not significantly different with or without methionine. Total cholesterol content of serum tended to be higher in coffee groups than non-coffee groups, and tended to be lower in methionine groups than non-methionine groups.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.7
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• pp.1022-1028
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• 2016

Milk composition is an imperative aspect which influences the quality of dairy products. The objective of study was to compare the chemical composition, nitrogen fractions and amino acids profile of milk from buffalo, cow, sheep, goat, and camel. Sheep milk was found to be highest in fat ($6.82%{\pm}0.04%$), solid-not-fat ($11.24%{\pm}0.02%$), total solids ($18.05%{\pm}0.05%$), protein ($5.15%{\pm}0.06%$) and casein ($3.87%{\pm}0.04%$) contents followed by buffalo milk. Maximum whey proteins were observed in camel milk ($0.80%{\pm}0.03%$), buffalo ($0.68%{\pm}0.02%$) and sheep ($0.66%{\pm}0.02%$) milk. The non-protein-nitrogen contents varied from 0.33% to 0.62% among different milk species. The highest r-values were recorded for correlations between crude protein and casein in buffalo (r = 0.82), cow (r = 0.88), sheep (r = 0.86) and goat milk (r = 0.98). The caseins and whey proteins were also positively correlated with true proteins in all milk species. A favorable balance of branched-chain amino acids; leucine, isoleucine, and valine were found both in casein and whey proteins. Leucine content was highest in cow ($108{\pm}2.3mg/g$), camel ($96{\pm}2.2mg/g$) and buffalo ($90{\pm}2.4mg/g$) milk caseins. Maximum concentrations of isoleucine, phenylalanine, and histidine were noticed in goat milk caseins. Glutamic acid and proline were dominant among non-essential amino acids. Conclusively, current exploration is important for milk processors to design nutritious and consistent quality end products.

• Journal of Nutrition and Health
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• v.13 no.4
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• pp.167-176
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• 1980

This study was conducted to compare effects of various types of dietary carboh ydrates fed with different levels of protein on the protein utilization in weanling rats. Sixty male Sprague-Dawley rats weighing $60{\pm}1.3grams$ were adapted for 1 week with 77% starch-15% casein diet. Then the animals divided into 12 groups according to body weight and fed each experimental diet for two weeks. Carbodydrates used were glucose, starch, and sucrose and the amount of protein given were 0g, 1g, 3g, 5g casein/day. Protein portion of the diet was fed in two seperate feedings per day while nonprotein portion was fed ad libitum. It seemed that there was no significant difference in the protein utilization by using the different kinds of carbohydrate, but in P.E.R., N.P.U., weights of organs and protein and lipid in total carcass, glucose groups were tended to be slightly lower than starch and sucrose groups. The larger the amount of casein given, the higher were the value of body weight gain, F.E.R., weights of organs, total lipid in carcass and the amount of nitrogen retention. On the while, the larger the amount of casein given, the lower were the value of the intake of non-protein portion, P.E.R., N.P.U, and the percentage of nitrogen retention.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.2
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• pp.161-164
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• 1993

To find out the effective indicators for identification and classification of different heat treatment, the contents of nitrogen fractions and the degrees of whey protein denaturation in market milks were investigated by Kjeldahl method. The contents of nitrogen fractions per 100ml raw milk were total nitrogen (431.3mg), casein nitrogen (341.0mg) and non-casein nitrogen(90.3mg), in which non-protein nitrogen (31.6mg) and denatured whey protein nitrogen (58.8mg), while those of LTLT, HTST, UHT pasteurized and UHT sterilized showed different values. The degrees of whey protein denaturation were 26.7%(LTLT), 32.9%(HTST), 60.7%(UHT pasteurized) and 38.4%(UHT sterilized), respectively. As the higher temperature was applied for the treatment of milk, the degree of the whey protein denaturation was higher. Remarkable differences in the degree of whey protein denaturation according to the heating methods were observed.

• Animal Bioscience
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• v.35 no.2
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• pp.260-271
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• 2022

Objective: We aimed to investigate the effect of the differing amino acid (AA) release dynamics of two protein sources on the growth performance, nitrogen deposition, plasma biochemical parameters, and muscle synthesis and degradation of piglets when included in their diets at normal and low concentrations. Methods: Forty-eight piglets (Duroc×Landrace×Large White) with initial body weight of 7.45±0.58 kg were assigned to six groups and fed one of 6 diets. The 6 dietary treatments were arranged by 3×2 factorial with 3 protein sources and 2 dietary protein levels. They are NCAS (a normal protein content with casein), NBlend (a normal protein content with blend of casein and corn gluten meal), NCGM (a normal protein content with corn gluten meal), LCAS (a low protein content with casein), LBlend (a low protein content with blend of casein and corn gluten meal), LCGM (a low protein content with corn gluten meal). The release dynamics of AA in these diets were determined by in vitro digestion. The digestibility, utilization and biological value of nitrogen in piglets were determined by micro Kjeldahl method. Plasma insulin was measured by enzyme-linked immunosorbent assay kits. The protein expression of mediators of muscle synthesis and degradation was determined by western blotting. Results: Although the consumption of a low-protein diet supplemented with crystalline AA was associated with greater nitrogen digestion and utilization (p<0.05), the final body weight, growth performance, nitrogen deposition, and phosphorylation of ribosomal protein S6 kinase 1 and eIF4E binding protein 1 in the muscle of pigs in the low-protein diet-fed groups were lower than those of the normal-protein diet-fed groups (p<0.05) because of the absence of non-essential AA. Because of the more balanced release of AA, the casein (CAS) and Blend-fed groups showed superior growth performance, final body weight and nitrogen deposition, and lower expression of muscle ring finger 1 and muscle atrophy F-box than the CGM-fed groups (p<0.05). Conclusion: We conclude that the balanced release of AA from CAS containing diets and mixed diets could reduce muscle degradation, favor nitrogen retention, % intake and improve growth performance in pigs consuming either a normal- or low-protein diet.

• Korean Journal of Agricultural Science
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• v.14 no.2
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• pp.301-308
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• 1987

The results of experiment to find out the optimum pasteurization condition by heating from $50^{\circ}C$ to $70^{\circ}C$ at intervals of $5^{\circ}C$ and to review chemical composition, microbiological aspects and keeping quality were summarized as follows: 1. The milk sample pasteurized at $50-70^{\circ}C$ showed the decreased pH value from 6.55 to 6.42 while the contents of protein, fat, lactose and ash did not have significant changes. 2. Non-casein nitrogen and filterable nitrogen decreased while casein nitrogen and non protein nitrogen increased as the heat treatment increased. 3. The content of calcium and vitamin C decreased and artificial digestibility for the pasteruized milk increased from 14.07% to 20.00% by the heat treatment. 4. Milk pasteurized at $65^{\circ}C$ had viable bacteria counts $1.3{\times}10^4/m{\ell}$, coliforms negative, psychrotrophic bacteria $9.5{\times}10^2/m{\ell}$ and 99.0% pasteurization effect. 5. Milk pasteurized at $65^{\circ}C$ did not show significant changes in chemical composition and microbiological aspects at $4^{\circ}C$ in refrigerator.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.10a
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• pp.337-339
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• 2004

본 연구에서는 생리 활성 효과가 기대되며, 기능적으로 활성도가 높은 뽕잎을 실용적으로 활용하는 방안으로 뽕잎의 치즈 원유 첨가비를 달리한 (0.3%, 0.6%, 0.9%) 아펜젤러 치즈를 제조하였다. 각 처리구별 치즈를 4개월간 숙성하면서 숙성중 치즈의 생균수.pH NPN(non protein nitrogen), NCN(non casein nitrogen), WSN (water soluble nitrogen)의 함량변화를 조사하였다. 치즈 첨가함량별 치즈제조 및 숙성 결과 높은 숙성도와 관능검사에서의 높은 기호도를 보인 0.6%구가 이상적인 뽕잎치즈 개발이 가능할 것으로 기대 되었다.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.05a
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• pp.298-300
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• 2004

본 연구에서는 생리 활성 효과가 기대되며, 기능적으로 활성도가 높은 복분자즙을 실용적으로 활용하는 방안으로 복분자즙의 치즈 원유 첨가비를 달리한 (2%, 4%, 6%) 아펜젤러 치즈를 제조 하였다. 각 처리구별 치즈를 4개월간 숙성하면서 숙성중 치즈의 생균수.pH NPN(non protein nitrogen) , NCN(non casein nitrogen) , WSN (water soluble nitrogen)의 함량 변화를 조사하였다. 치즈 첨가함량별 치즈제조 및 숙성 결과 4%구에서 높은 숙성도를 보였고 관능검사에서도 6%구에서 높은 기호도를 나타내 추가적인 연구가 수행된다면 이상적인 한국적 기능성 자연 치즈 개발이 가능할 것으로 기대 되었다.